In the previous chapters, we have built new applications in TypeScript. However, you might also have old code bases in JavaScript which you want to migrate to TypeScript. We will see how these projects can be converted to TypeScript.
You could rewrite the whole project from scratch, but that would require a lot of work for big projects. Since TypeScript is based on JavaScript, this transition can be done more efficiently.
Since the migration process is dependent on the project, this chapter can only give guidance. For various common topics, this chapter contains a recipe to migrate code. Migrating a project requires knowledge of the frameworks and the structure of the project.
The following steps are related to migrating a code base:
Gradually migrating to TypeScript
Adding TypeScript
Migrating each file
Refactoring the project